Problem: Find the slope and y-intercept of the line that is ${\text{parallel}}$ to $\enspace {y = \dfrac{1}{2}x + 4}\enspace$ and passes through the point ${(-3, -3)}$. ${1}$ ${2}$ ${3}$ ${4}$ ${5}$ ${6}$ ${7}$ ${8}$ ${9}$ ${\llap{-}2}$ ${\llap{-}3}$ ${\llap{-}4}$ ${\llap{-}5}$ ${\llap{-}6}$ ${\llap{-}7}$ ${\llap{-}8}$ ${\llap{-}9}$ ${1}$ ${2}$ ${3}$ ${4}$ ${5}$ ${6}$ ${7}$ ${8}$ ${9}$ ${\llap{-}2}$ ${\llap{-}3}$ ${\llap{-}4}$ ${\llap{-}5}$ ${\llap{-}6}$ ${\llap{-}7}$ ${\llap{-}8}$ ${\llap{-}9}$
Answer: Parallel lines have the same slope. The slope of the blue line is ${\dfrac{1}{2}}$ , so the equation of our parallel line will be of the form $\enspace {y = \dfrac{1}{2}x + b}\enspace$ We can plug our point, $(-3, -3)$ , into this equation to solve for ${b}$ , the y-intercept. $-3 = {\dfrac{1}{2}}(-3) + {b}$ $-3 = -\dfrac{3}{2} + {b}$ $-3 + \dfrac{3}{2} = {b} = -\dfrac{3}{2}$ The equation of the parallel line is $\enspace {y = \dfrac{1}{2}x - \dfrac{3}{2}}\enspace$. ${m = \dfrac{1}{2}, \enspace b = -\dfrac{3}{2}}$